Light-emitting device
A light-emitting device includes a growth substrate, a plurality of light-emitting diode units formed on the growth substrate and arranged in a closed loop, an electrode directly formed on the growth substrate, an electrical connection structure formed on the growth substrate and connecting the plurality of light-emitting diode units with the electrode, and a plurality of rectifying diodes connecting to respective nodes of the closed loop.
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The present application is a continuation application of U.S. patent application Ser. No. 13/148,544, filed on Nov. 14, 2011, which is a national stage application of PCT Application No. PCT/CN2009/074422, filed on Oct. 13, 2009, and claims priority to Chinese Application No. 200910007059.2, filed on Feb. 9, 2009, the entire contents of which are herein incorporated by reference.
TECHNICAL FIELDThe application relates to a light-emitting device, and more particularly to a light-emitting device having at least one electronic element and at least one light-emitting diode array chip, which are arranged on a submount, and can be directly used with an alternative current source.
DESCRIPTION OF BACKGROUND ARTLight-emitting diode (LEDs) can emit light energy in the presence of energy difference resulted from movement of electrons between the n-type semiconductor and the p-type semiconductor. With this mechanism, the LEDs can generate cool light in contrary to incandescent bulbs. Besides, the LEDs are durable and compact, and have long lifespan and low energy-consumption. Accordingly, the LEDs become promising candidates in the market to be the next-generation lighting products in place of the conventional lighting sources, and are already applied to various fields such as traffic lights, backlight modules, street lights, and medical equipment.
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To replace a conventional lighting device, the light-emitting diode element 100 must work on a high voltage condition of 100V˜240V, which may bring about a high temperature issue after long time operation. Under the high voltage and high temperature conditions, an electronmigration effect, which is a result of movement of metal ions caused by a mixed effect of the temperature and the electron wind, can be easily found in an electronic device. Generally, the electronmigration of metal ions occurs easily at high temperature. In the light-emitting diode element, the metal ions may diffuse from the electrode to the active region by the effect of the electric current at high temperature. For example, the electronmigration may occur easily in the electrode material such as indium tin oxide (ITO) and silver. Moreover, the element may fail due to voids caused by the electronmigration in solder or tiny metal connection.
As described above, the reliability of the light-emitting diode element for alternative current usage can be seriously deteriorated at high temperature and high voltage environment.
SUMMARY OF THE DISCLOSUREA light-emitting device in accordance with one embodiment of the present application includes a growth substrate, a plurality of light-emitting diode units formed on the growth substrate and arranged in a closed loop, an electrode directly formed on the growth substrate, an electrical connection structure formed on the growth substrate and connecting the plurality of light-emitting diode units with the electrode, and a plurality of rectifying diodes connecting to respective nodes of the closed loop.
The embodiments are described hereinafter in accompany with
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The electronic element 22 can be one or more passive elements, such as rectifier(s), resistor(s), capacitor(s), and inductor(s).
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In the second embodiment listed in the table, the light-emitting device emits a warm white light. The power ratio of all blue light-emitting diode array chip(s) to all red light-emitting diode array chip(s) is about 3:1. For example, there are three blue light-emitting diode array chips and one red light-emitting diode array chip. Each blue light-emitting diode array chip has eight light-emitting diode units (hereinafter defined as “blue light-emitting diode units”) which are connected in series. The red light-emitting diode array chip has twelve light-emitting diode units (hereinafter defined as “red light-emitting diode units”) which are connected in series. Therefore, in one light-emitting device, the quantity ratio of all blue light-emitting diode units to all red light-emitting diode units is 24:12 (2:1). Provided one blue light-emitting diode unit has a forward voltage of about 3V and one red light-emitting diode unit has a forward voltage of about 2V, each of the blue and red light-emitting diode array chips can work on 24V, which can be called as a high voltage direct current (DC) array chip. Consequently, the light-emitting diode array chips of the 2×2 matrix can work on 96V. When the light-emitting device is driven to emit the blue light and the red light, the power ratio of the blue light to the red light is about 3:1. Provided the light-emitting diode array matrix is serially connected to a predetermined resister and the aforementioned rectifier having a bridge circuit, the light-emitting device can be used in an AC power system of 110V. In the present embodiment, the power ratio of all blue light-emitting diode array chip(s) to all red light-emitting diode array chip(s) is about 2˜4, preferably 2.6˜3.4. Alternatively, the quantity ratio of all blue light-emitting diode unit(s) to all red light-emitting diode unit(s) is about 4/3˜8/3, which can generate a warm white light whose color temperature is between 2000K and 5000K, preferably between 2000K and 3500K. In another embodiment, the red light-emitting diode array chip can be replaced by several non-array-type red light-emitting diode chips which are connected with each other in series. The quantity of the non-array-type red light-emitting diode chips is equal to the quantity of all red light-emitting diode units in the replaced red light-emitting diode array chip. In specific, the non-array-type red light-emitting diode chip has only one red light-emitting diode unit whose forward voltage is about 2V.
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Furthermore, the first conductivity type semiconductor layer 520 of the light-emitting diode unit 540 is electrically connected to the second conductivity type semiconductor layer 524 of the neighboring light-emitting diode unit 540′. With this arrangement, a series-connected closed loop can be formed, and consequently the light-emitting diode array chip 500 is formed.
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The diode units 54 include light-emitting diode units 540 and rectifying light-emitting diode units 542a, 542b, 542c, 542d. The electrode 56a is electrically connected to a first conductivity type semiconductor layer (not shown) of the rectifying light-emitting diode unit 542a and a second conductivity type semiconductor layer (not shown) of the rectifying light-emitting diode unit 542b by the electrical connection structures 58. The electrode 56b is electrically connected to a first conductivity type semiconductor layer (not shown) of the rectifying light-emitting diode unit 542c and a second conductivity type semiconductor layer (not shown) of the rectifying light-emitting diode unit 542d by the electrical connection structures 58. In addition, the light-emitting diode units 540 are arranged in a series-connected closed loop. To form a bridge circuit, the rectifying light-emitting diode units 542a, 542b, 542c, 542d are respectively connected to different nodes w, x, y, z in the series-connected closed loop.
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Although the invention is explained above, it is not limited the range, the sequence in practice, the material in practice, or the method in practice is. Any modification or decoration for this invention is not away from the spirit and the range of this invention.
Claims
1. A light-emitting device comprising:
- a first light-emitting diode chip comprising: a substrate; a plurality of light-emitting diode units epitaxially connected to the substrate, having a sidewall, and arranged in a closed loop; an electrode formed on the substrate; an insulating layer having a shape substantially conforming to the sidewall; a metal layer formed on the insulating layer, and electrically connecting the plurality of light-emitting diode units and the electrode; a plurality of rectifying diodes epitaxially connected to the substrate and connected to respective nodes of the closed loop; and an electrical connection structure formed on a predetermined one of the plurality of rectifying diodes and comprising a first portion and a second portion separated from the first portion, wherein the first portion and the second portion are located on two corners which are located on a diagonal line of the predetermined one of the plurality of rectifying diodes, wherein the plurality of light-emitting diode units comprises at least two light-emitting diode units, the at least two light-emitting diode units are configured to alternately emit light when the light-emitting device is operated, and wherein each of the plurality of light-emitting diode units is formed in a rectangular shape.
2. The light-emitting device of claim 1, wherein the plurality of light-emitting diode units and the plurality of rectifying diodes have a same epitaxial stacked layer.
3. The light-emitting device of claim 1, wherein the plurality of rectifying diodes is physically separated by the plurality of light-emitting diode units.
4. The light-emitting device of claim 1, wherein the plurality of light-emitting diode units has more than three light-emitting diode units physically arranged in a line.
5. The light-emitting device of claim 1, further comprising a submount on which the first light-emitting diode chip is arranged.
6. The light-emitting device of claim 5, further comprising a second light-emitting diode chip formed on the submount and having a peak wavelength different from the first light-emitting diode chip.
7. The light-emitting device of claim 5, further comprising an electronic element formed on the submount and including a resistor, a capacitor, or an inductor.
8. The light-emitting device of claim 1, further comprising an encapsulation material covering the first light-emitting diode chip.
9. The light-emitting device of claim 1, further comprising a wavelength converting layer arranged on the first light-emitting diode chip.
10. The light-emitting device of claim 1, wherein the plurality of light-emitting diode units is connected in series.
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Type: Grant
Filed: Aug 18, 2015
Date of Patent: Jul 31, 2018
Patent Publication Number: 20150357371
Assignee: EPISTAR CORPORATION (Hsinchu)
Inventors: Chao-Hsing Chen (Hsinchu), Schang-Jing Hon (Hsinchu), Alexander Chan Wang (Hsinchu), Li-Tian Liang (Hsinchu), Chin-Yung Fan (Hsinchu), Chien-Kai Chung (Hsinchu), Min-Hsun Hsieh (Hsinchu)
Primary Examiner: Johannes P Mondt
Application Number: 14/829,262
International Classification: H01L 27/15 (20060101); H01L 25/065 (20060101); H01L 25/075 (20060101); H01L 27/32 (20060101); H01L 33/50 (20100101); H01L 33/62 (20100101);